Dead-ammonite bounce
死鹦鹉螺化石反弹
Life recovered from its worst extinction much faster than previously realized
生命从他最严重的灭绝中恢复的比之前了解到的情况快的多
Jul 5th 2010
THE dinosaurs went out with a bang. Most paleontologists agree that those creatures and much of the rest of Mesozoic life ended when the Earth collided with an asteroid or a comet 65m years ago. But the Mesozoic, too, began with a mass extinction. Some 251m years ago, the effluvia of Siberian volcanoes wiped out 95% of life in the seas, and almost as much on the land, in an episode known as the Great Dying. This was the end of the Permian period, and of the era of life called the Paleozoic. The survivors regrouped, re-evolved and turned into the Mesozoic species that led eventually to the dinosaurs, pterosaurs, ammonites and belemnites that generations of fossil hunters are familiar with.
随着一声巨响恐龙灭绝了。大多数古生物学家同意那些生物和剩下大部分的中生代生物都是在六千五百万年前地球和一颗小行星或者彗星相撞时灭绝。但是，中生代也是以一次大规模的物种灭绝开始的。大约两亿五千一百万年前，在大灭绝时期，西伯利亚火山的废渣歼灭了95%的海洋生物，陆地上也是差不多情形。这就是二叠纪以及整个古生代的终结。幸存者重新组合，重新进化，变成了中生代物种，并且最终变成了几代寻觅化石者熟悉的恐龙，翼龙，鹦鹉螺化石 和箭石 。
How that regrouping happened will be the topic of a presentation by Hugo Bucher, the director of the Palaeontological Institute at the University of Zurich, at the Third International Paleontological Congress in London on July 3rd. According to Dr Bucher, it occurred faster than anyone had previously thought, but also stuttered on the way as the volcanic activity waxed and waned.
探讨重新组合如何发生是苏黎世大学古生物研究所的所长雨果•布赫尔7月3日在伦敦的第三届国际古生物学大会上讲演的主题。根据布赫尔博士的研究，这种重组发生的比之前任何想的都要快，但是也在中途因为火山活动的几度活跃和沉寂而有所迟缓。
Until now, paleontologists have thought the recovery took tens of millions of years―a reflection either of the profundity of the Great Dying or of the toxic desert planet that the eruptions created. But that opinion was based on shaky data. Most rock sequences that straddle the end of the Permian are either incomplete or hard to date. Dr Bucher, however, has had the benefit of looking at a set of strata in southern China that were, until recently, off limits to foreign scientists.
到目前为止，古生物学家认为恢复需要几千万年的时间――原因要么是由于大灭绝的深重影响，要么是由于火山爆发导致地球变成有毒的荒漠。但是这些观点是建立在不太可靠的数据上的。大部分跨越了二叠纪的岩序列不是不够完整就是很难确定日期。但是布赫尔博士受益于能够有机会观察直到最近对于外国科学家仍然是禁区的中国南部的一系列地层。
These rocks consist of fossil-rich layers containing rapidly evolving marine organisms such as ammonites, interleaved with layers of volcanic ash. The ash contains minerals such as zircon that can be dated precisely from the radioactive decay of some of their components.
这些岩层富含化石，其中有快速进化的海洋生物，比如鹦鹉螺化石，岩层与火山灰岩交错排列。火山灰包含像锆石一类能够通过同位素的放射性衰变来精确确定年份的矿物质。
The result is 50 reliable time-points in a section that spans 10m years. Previously, the only dateable layers were from the moment the Permian ended and from a subsequent volcanic event some 14m years later. The ages of rocks between these two were little more than guesswork.
结果是跨度为一千万年的50个可靠的时间点。之前，唯一能够确定日期的岩层来自于二叠纪结束的时刻和随后大约一千四百万年的火山活动的时候。这两个时间之间的岩石的年龄都不过是猜测。
Dr Bucher's studies of the Chinese sections indicate two things. First, that there was not one mass extinction at the end of the Permian, but several. Second, the time the recovery took has been greatly overestimated. He says that species such as ammonites and conodonts (primitive eel-like creatures with teeth) had recovered within 1m years of the initial extinction. Another, smaller episode of volcanism 2m years later, which once again heated the planet and turned the seas acid, hammered life again―and again it recovered quickly.
布赫尔博士对于中国区域的研究表明了两件事情。第一，在二叠纪结束的时候并不是一个大规模灭绝，而是好几个。第二，物种恢复所需的时间被估计的过长了。他说，像鹦鹉螺化石和牙形刺（有牙齿的原始鳗类动物）等物种都在最初灭绝后一百万年内就恢复了。另外，二百年之后较短时期的火山活动再一次使得地球变热，海水变酸，从而再一次打击了生物，但是同样恢复的很快。
Only two of 15 ammonite families survived this second extinction, says Dr Bucher, but within a million years those two had speciated into 15, and ammonites had regained their former diversity. There also seems to have been a third episode of environmental disruption before conditions stabilised, around 6m years after the initial extinction, and life was left in peace to reconstruct complex ecosystems of the sort that had existed before. Over the next 4m years, habitats that the extinction had eradicated―reefs in the sea and forests on land―re-established themselves, albeit with entirely novel species. To quote Voltaire, then, "Le malheur des uns fait le bonheur des autres."
布赫尔博士表示，15个鹦鹉螺家族中只有2个在第二次灭绝中存活了下来。但是仅仅在一百万年里这两种就扩展到了15种，鹦鹉螺又恢复了其原来的多样性。在环境稳定下来之前似乎还有第三段时期的环境扰动，发生在最初的灭绝之后大约六百万年后，之后生物就在平静的环境下开始重建之前存在过的那种复杂的生态系统。在接下来的四百万年里，被灭绝毁灭了的栖息地――海中的珊瑚礁和陆地上的森林――重新建立起来，尽管繁衍的是全新的物种。伏尔泰曾经说过："个别的不幸创造出整体的幸福。"
死鹦鹉螺化石反弹
Life recovered from its worst extinction much faster than previously realized
生命从他最严重的灭绝中恢复的比之前了解到的情况快的多
Jul 5th 2010
THE dinosaurs went out with a bang. Most paleontologists agree that those creatures and much of the rest of Mesozoic life ended when the Earth collided with an asteroid or a comet 65m years ago. But the Mesozoic, too, began with a mass extinction. Some 251m years ago, the effluvia of Siberian volcanoes wiped out 95% of life in the seas, and almost as much on the land, in an episode known as the Great Dying. This was the end of the Permian period, and of the era of life called the Paleozoic. The survivors regrouped, re-evolved and turned into the Mesozoic species that led eventually to the dinosaurs, pterosaurs, ammonites and belemnites that generations of fossil hunters are familiar with.
随着一声巨响恐龙灭绝了。大多数古生物学家同意那些生物和剩下大部分的中生代生物都是在六千五百万年前地球和一颗小行星或者彗星相撞时灭绝。但是，中生代也是以一次大规模的物种灭绝开始的。大约两亿五千一百万年前，在大灭绝时期，西伯利亚火山的废渣歼灭了95%的海洋生物，陆地上也是差不多情形。这就是二叠纪以及整个古生代的终结。幸存者重新组合，重新进化，变成了中生代物种，并且最终变成了几代寻觅化石者熟悉的恐龙，翼龙，鹦鹉螺化石 和箭石 。
How that regrouping happened will be the topic of a presentation by Hugo Bucher, the director of the Palaeontological Institute at the University of Zurich, at the Third International Paleontological Congress in London on July 3rd. According to Dr Bucher, it occurred faster than anyone had previously thought, but also stuttered on the way as the volcanic activity waxed and waned.
探讨重新组合如何发生是苏黎世大学古生物研究所的所长雨果•布赫尔7月3日在伦敦的第三届国际古生物学大会上讲演的主题。根据布赫尔博士的研究，这种重组发生的比之前任何想的都要快，但是也在中途因为火山活动的几度活跃和沉寂而有所迟缓。
Until now, paleontologists have thought the recovery took tens of millions of years―a reflection either of the profundity of the Great Dying or of the toxic desert planet that the eruptions created. But that opinion was based on shaky data. Most rock sequences that straddle the end of the Permian are either incomplete or hard to date. Dr Bucher, however, has had the benefit of looking at a set of strata in southern China that were, until recently, off limits to foreign scientists.
到目前为止，古生物学家认为恢复需要几千万年的时间――原因要么是由于大灭绝的深重影响，要么是由于火山爆发导致地球变成有毒的荒漠。但是这些观点是建立在不太可靠的数据上的。大部分跨越了二叠纪的岩序列不是不够完整就是很难确定日期。但是布赫尔博士受益于能够有机会观察直到最近对于外国科学家仍然是禁区的中国南部的一系列地层。
These rocks consist of fossil-rich layers containing rapidly evolving marine organisms such as ammonites, interleaved with layers of volcanic ash. The ash contains minerals such as zircon that can be dated precisely from the radioactive decay of some of their components.
这些岩层富含化石，其中有快速进化的海洋生物，比如鹦鹉螺化石，岩层与火山灰岩交错排列。火山灰包含像锆石一类能够通过同位素的放射性衰变来精确确定年份的矿物质。
The result is 50 reliable time-points in a section that spans 10m years. Previously, the only dateable layers were from the moment the Permian ended and from a subsequent volcanic event some 14m years later. The ages of rocks between these two were little more than guesswork.
结果是跨度为一千万年的50个可靠的时间点。之前，唯一能够确定日期的岩层来自于二叠纪结束的时刻和随后大约一千四百万年的火山活动的时候。这两个时间之间的岩石的年龄都不过是猜测。
Dr Bucher's studies of the Chinese sections indicate two things. First, that there was not one mass extinction at the end of the Permian, but several. Second, the time the recovery took has been greatly overestimated. He says that species such as ammonites and conodonts (primitive eel-like creatures with teeth) had recovered within 1m years of the initial extinction. Another, smaller episode of volcanism 2m years later, which once again heated the planet and turned the seas acid, hammered life again―and again it recovered quickly.
布赫尔博士对于中国区域的研究表明了两件事情。第一，在二叠纪结束的时候并不是一个大规模灭绝，而是好几个。第二，物种恢复所需的时间被估计的过长了。他说，像鹦鹉螺化石和牙形刺（有牙齿的原始鳗类动物）等物种都在最初灭绝后一百万年内就恢复了。另外，二百年之后较短时期的火山活动再一次使得地球变热，海水变酸，从而再一次打击了生物，但是同样恢复的很快。
Only two of 15 ammonite families survived this second extinction, says Dr Bucher, but within a million years those two had speciated into 15, and ammonites had regained their former diversity. There also seems to have been a third episode of environmental disruption before conditions stabilised, around 6m years after the initial extinction, and life was left in peace to reconstruct complex ecosystems of the sort that had existed before. Over the next 4m years, habitats that the extinction had eradicated―reefs in the sea and forests on land―re-established themselves, albeit with entirely novel species. To quote Voltaire, then, "Le malheur des uns fait le bonheur des autres."
布赫尔博士表示，15个鹦鹉螺家族中只有2个在第二次灭绝中存活了下来。但是仅仅在一百万年里这两种就扩展到了15种，鹦鹉螺又恢复了其原来的多样性。在环境稳定下来之前似乎还有第三段时期的环境扰动，发生在最初的灭绝之后大约六百万年后，之后生物就在平静的环境下开始重建之前存在过的那种复杂的生态系统。在接下来的四百万年里，被灭绝毁灭了的栖息地――海中的珊瑚礁和陆地上的森林――重新建立起来，尽管繁衍的是全新的物种。伏尔泰曾经说过："个别的不幸创造出整体的幸福。"
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